Getting Month values for specific year - sql

Question

Fisc_prd stands for month
fisc_yr stands for year
I need the result in such a way that if current month is 01(that is Jan) then i need all the period for previous year i.e 1 to 12 and if the current month is not equal to 01 then i need all the period for current year less than current month(e.g if the current month is 3 then i need 1 to 2 as fisc_prd)
I can only get all the fisc_prd for previous year but cant get fisc_prd less than current month for current year. In Below query, CALENDAR table contains all the Month and Year values.By usig this query i can get all the fisc_prd for previous year when current month is 01.
SELECT FISC_PRD,FISC_YR FROM CALENDAR WHERE FISC_YR=(SELECT DECODE(TO_NUMBER(TO_CHAR(SYSDATE,'MM')),01,(TO_NUMBER(TO_CHAR(SYSDATE,'YYYY'))-1) ,TO_NUMBER(TO_CHAR(SYSDATE,'YYYY'))) FROM DUAL)
Please share your ideas

Answer 1

If you're basing this on the current date then you can use a connect-by hierarchical query to get the period and year:
select extract(month from add_months(sysdate, 1-level)) as fisc_prd,
extract(year from add_months(sysdate, 1-level)) as fisc_year
from dual
where level > 1
connect by level <= case when extract(month from sysdate) = 1 then 13
else extract(month from sysdate) end;
Today that gives:
FISC_PRD FISC_YEAR
---------- ----------
1 2015
To check how it behaves for other dates you can use a modified version that uses a specific date but the same logic; I'm using a bind variable here:
variable dt varchar2;
exec :dt := '2015-01-17';
select extract(month from add_months(to_date(:dt, 'YYYY-MM-DD'), 1-level)) as fisc_prd,
extract(year from add_months(to_date(:dt, 'YYYY-MM-DD'), 1-level)) as fisc_year
from dual
where level > 1
connect by level <= case
when extract(month from to_date(:dt, 'YYYY-MM-DD')) = 1 then 13
else extract(month from to_date(:dt, 'YYYY-MM-DD'))
end;
FISC_PRD FISC_YEAR
12 2014
11 2014
10 2014
9 2014
8 2014
7 2014
6 2014
5 2014
4 2014
3 2014
2 2014
1 2014
Changing the value of dt seems to give the result you described; for example with
exec :dt := '2015-03-17';
you get:
FISC_PRD FISC_YEAR
---------- ----------
2 2015
1 2015
But this is just to test the logic, you can just use sysdate rather than a bind variable.
The 1-level and using 13 if the current month is January are because you don't want the current month to be included in the result.

Answer 2

This ought to work:
with sample_data as (select to_number(to_char(add_months(sysdate, 6 - level), 'mm')) fisc_prd,
to_number(to_char(add_months(sysdate, 6 - level), 'yyyy')) fisc_yr
from dual
connect by level <= 24)
select fisc_prd,
fisc_yr
from sample_data
where case when to_char(sysdate, 'mm') = '01' then to_number(to_char(sysdate, 'yyyy')) -1
else to_number(to_char(sysdate, 'yyyy')) end = fisc_yr
and case when to_char(sysdate, 'mm') = '01' then 13
else to_number(to_char(sysdate, 'mm')) end > fisc_prd;

Answer 3

If your colum "FISC_YR" is datetime datatype then the below query will works for you
SELECT FISC_PRD,FISC_YR
FROM CALENDAR
WHERE
(month(getdate())!=1 AND month(FISC_YR) in(month(getdate())- 1,month(getdate())-2) AND year(getdate())=year(FISC_YR))
OR
(month(getdate())=1 AND year(getdate())-1=year(FISC_YR))